Currently, application of the MIMO technology in the wireless network mainly aims at increasing the downlink system capacity with a plurality of data streams aimed at a single terminal, thus, most of the terminals are configured with a plurality of antennae, specifically a plurality of receiving chains to accomplish downlink MIMO reception, while configured with only one transmitting chain. With the developments of technologies and increased requirements, a terminal has a plurality of transmitting chains for uplink data transmission, but the maximal channel capacity cannot be achieved since the traditional transmitting method uses the open-loop technology, such as various transmit diversity methods, antenna selection or spatial multiplexing technologies and does not measure the spatial channel state information.
So-called spatial multiplexing uses a plurality of antennas at the receiving end and the transmitting end to make full use of the multipath components in the spatial propagation, and uses a plurality of data channels, such as MIMO sub-channels, on the same frequency band to transmit signals, thereby make the capacity linearly increased with the increasing of the number of the antennae. The process of uplink transmission of the existing spatial multiplexing technology is as follows: when uplink transmission is performed using the spatial multiplexing technology, the terminal firstly converts the signals to be transmitted into several parallel signal streams by serial-parallel conversion, and simultaneously transmits them using individual antenna on the same frequency band. Due to the multipath propagation, each antenna will produce a different spatial signal at the base station, and the base station distinguishes the individual data streams using signal differences.
In the above transmission process, the multi-antenna technology is only a theoretical method. In practice, the uplink data transmission of the MIMO system is usually performed by the terminal which maps the data streams directly onto each antenna and transmits to the base station.
The shortcoming of the existing art is: the existing method for uplink spatial transmission, no matter using multi-antenna or using single-antenna, does not make full use of the spatial channel state information; therefore, the system cannot achieve a maximal channel capacity.